Information processing device, information processing device control method and control program

ABSTRACT

An information processing device collects information on an operating state of a communication system formed of a master device that manages communication over a network and at least one slave device connected to the network and capable of performing communication as instructed by the master device. The master device and the slave device record communication log entries regarding time information and a communication state in accordance with communication processing. The information processing device includes an acquiring section that acquires communication log entries from at least one of the master device and the slave device, a log entry rearranging section that rearranges the acquired communication log entries based on the time information, and a log entry extracting section that extracts, out of the rearranged communication log entries, any communication log entry recorded within a predetermined period of time from occurrence of a communication log entry including communication abnormality information.

TECHNICAL FIELD

The present invention relates to an information processing device thatcollects information on the operating state of a communication systemformed of a master device that manages communication over a network andat least one slave device that is capable of performing communication asinstructed by the master device, a method for controlling theinformation processing device, and a control program.

RELATED ART

A PLC (Programmable Logic Controller) that is used as a control devicefor industrial equipment and the like is constituted by a plurality ofunits including a CPU unit that performs overall control of the PLC, acommunication unit that performs communication, an I/O unit thatperforms input/output of signals, and the like. In order for such a PLCto perform the control as desired by a user, the user designs thedetails of control of the PLC, that is to say, the user designs a userprogram, for example. At this time, generally, the user installspredetermined software on a personal computer (computer) and uses theinstalled software.

“Omron Corporation, CX-Programmer support software Ver. 9.0,Japanese-language version (first sold in 2009)” (Non-Patent Document 1),for example, discloses a development support device that supports thedevelopment of such a PLC.

When maintenance work is to be performed on a PLC with respect to whichdesign and the like of the details of control is performed using such adevelopment support device, a personal computer (computer), for example,is connected to the PLC. Support software for performing maintenancework on the PLC is installed on the personal computer in advance.

Specifically, the support software contains the method for handling thePLC and guide information (contents) for troubleshooting.

For a PLC, codes (event codes) that unambiguously indicate the state ofthe PLC or the operation of the PLC are predetermined. In this regard,JP 2012-208931A discloses a technology that collects information on theoperating state of a PLC and displays the information on a display.

RELATED ART DOCUMENTS Patent Documents

-   Patent Document 1: JP 2012-208931A

Non-Patent Documents

-   Non-Patent Document 1: “Omron Corporation, CX-Programmer support    software Ver. 9.0, Japanese-language version (first sold in 2009)”

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

However, according to conventional configurations, with respect to asystem that uses a plurality of PLCs, information on an abnormal (error)condition stored in the individual PLCs is collected, and the errorcondition is merely displayed. Thus, even when mutually related errorconditions occur as in the case of a communication abnormality, thesituation cannot be easily recognized. Accordingly, there is a problemin that it is difficult to easily locate a fault to be eliminated.

The present invention was made to address problems such as thatdescribed above, and it is an object thereof to provide an informationprocessing device that collects information on the operating state of acommunication system formed of a master device that managescommunication over a network and at least one slave device that iscapable of performing communication as instructed by the master device,the information processing device being capable of easily recognizingmutually related error conditions, a method for controlling theinformation processing device, and a control program.

Means for Solving the Problems

An information processing device according to an aspect of the presentinvention is an information processing device that collects informationon an operating state of a communication system formed of a masterdevice that manages communication over a network and at least one slavedevice that is connected to the network and that is capable ofperforming communication as instructed by the master device, wherein themaster device and the slave device record communication log entriesregarding time information and a communication state in accordance withcommunication processing, the information processing device including anacquiring section that acquires communication log entries from at leastone of the master device and the slave device, a log entry rearrangingsection that rearranges the acquired communication log entries based onthe time information, and a log entry extracting section that extracts,out of the communication log entries rearranged by the log entryrearranging section, any communication log entry recorded within apredetermined period of time from occurrence of a communication logentry including communication abnormality information that indicatesoccurrence of an abnormality in communication as the communicationstate.

Preferably, the information processing device may further include adisplay section that displays the extracted communication log entries.

Preferably, the communication system may be provided with a safety slavedevice that is connected to a device related to safety and a safetymaster device for managing the safety slave device, the safety slavedevice or the safety master device may be connected to at least one ofthe master device and the slave device, and the safety master device maybe configured to issue an instruction to the safety slave device via themaster device. The safety master device and the safety slave device mayrecord communication log entries regarding the time information and thecommunication state in accordance with the communication processing. Theacquiring section may further acquire communication log entries from atleast one of the safety master device and the safety slave device.

Preferably, the information processing device may further include anabnormality cause analysis database that stores a cause of anabnormality and an abnormality pattern associated therewith, theabnormality pattern including at least one communication log entryincluding communication abnormality information, and an abnormalitycause identifying section that identifies a cause of the abnormalitywith respect to the extracted communication log entries by referring tothe abnormality cause analysis database.

A method for controlling an information processing device according toanother aspect of the present invention is a method for controlling aninformation processing device that collects information on an operatingstate of a communication system formed of a master device that managescommunication over a network and at least one slave device that isconnected to the network and that is capable of performing communicationas instructed by the master device, wherein communication log entriesregarding time information and a communication state are recorded in themaster device and the slave device in accordance with communicationprocessing, the method including the steps of acquiring communicationlog entries from at least one of the master device and the slave device,rearranging the acquired communication log entries based on the timeinformation, and extracting, out of the rearranged communication logentries, any communication log entry recorded within a predeterminedperiod of time from occurrence of a communication log entry includingcommunication abnormality information that indicates occurrence of anabnormality in communication as the communication state.

A control program of an information processing device according toanother aspect of the present invention is a control program of aninformation processing device that collects information on an operatingstate of a communication system formed of a master device that managescommunication over a network and at least one slave device that isconnected to the network and that is capable of performing communicationas instructed by the master device, the control program being executableon a computer of the information processing device, whereincommunication log entries regarding time information and a communicationstate are recorded in the master device and the slave device inaccordance with communication processing, the program causing thecomputer to execute processing including the steps of acquiringcommunication log entries from at least one of the master device and theslave device, rearranging the acquired communication log entries basedon the time information, and extracting, out of the rearrangedcommunication log entries, any communication log entry recorded within apredetermined period of time from occurrence of a communication logentry including communication abnormality information that indicatesoccurrence of an abnormality in communication as the communicationstate.

Effects of the Invention

It is possible to easily identify mutually related error conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows diagrams illustrating configurations of a communicationsystem according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram that schematically shows a functionalconfiguration of a master PLC 20.

FIG. 3 is a block diagram that schematically shows a hardwareconfiguration of a PC 10 according to Embodiment 1.

FIG. 4 is a diagram illustrating functional blocks that are executed bya CPU 11 of the PC 10 according to Embodiment 1.

FIG. 5 is a diagram illustrating a case in which a communicationabnormality occurs in the communication system according to Embodiment1.

FIG. 6 is a diagram illustrating an example of communication log entriesthat are processed by the PC 10 of the communication system according toEmbodiment 1.

FIG. 7 is a diagram illustrating a case in which a communicationabnormality occurs in a communication system according to a modificationof Embodiment 1.

FIG. 8 is a diagram illustrating an example of communication log entriesthat are processed by the PC 10 of the communication system according tothe modification of Embodiment 1.

FIG. 9 is a diagram illustrating functional blocks that are executed bythe CPU 11 of the PC 10 according to Embodiment 2.

FIG. 10 is a diagram illustrating display of a troubleshooting log thatis displayed on a display section 13 according to Embodiment 2.

EMBODIMENTS OF THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings. The following description denoteslike or corresponding portions in the drawings by like referencenumerals, and does not repeat the descriptions thereof.

Embodiment 1

FIG. 1 shows diagrams illustrating configurations of a communicationsystem according to Embodiment 1 of the present invention.

Referring to FIG. 1(A), a communication system according to Embodiment 1includes a PC (personal computer) 10, which is an information processingdevice, a master PLC 20, a slave PLC 22, a slave PLC 24, and a network26 to which the PLCs are connected.

In the present example, a configuration in which three PLCs areconnected to the network 26 is described as an example. However, thenumber of PLCs is not limited to this, and a configuration is alsopossible in which a plurality of further PLCs are connected.

Predetermined software for causing the PC 10 to perform maintenance workon the PLCs as a development support device is installed on the PC 10,and processing for maintenance of the PLCs based on that software isexecuted. In the present example, the PC 10 is connected to the masterPLC 20 and acquires information on the state of the master PLC 20 aswell as the slave PLCs 22 and 24 and the like via the master PLC 20.Then, various types of processing for performing the maintenance work onthe PLCs are executed based on the acquisition result. For example,display or the like of guide information for troubleshooting isperformed. In the present example, a case in which information on thestate of the PLCs is acquired via the master PLC 20 as shown in FIG.1(A) is described. However, the present invention is not particularlylimited to this configuration. A configuration may also be adopted inwhich the PC 10 is connected to the network 26 and acquires informationon the state of the PLCs as shown in FIG. 1(B).

Generally, PLCs of a standard type (standard PLCs) that control ordinaryobjects to be controlled and PLCs of a safety type (safety PLCs) thatare used for safety are known as PLCs that are used to, for example,control production equipment in factories.

A standard PLC is configured by combining a plurality of units such as aCPU unit that executes calculations based on a control program, an inputunit to which input devices are connected and which captures ON and OFFsignals of the input devices as input signals, an output unit to whichoutput devices are connected and which transmits output signals to theoutput devices, a communication unit that transmits/receives datato/from other devices connected to the network, and a power unit thatsupplies power to the various units. These units are electricallyconnected to one another by an internal bus, and data is exchangedbetween predetermined units via the internal bus.

For example, the CPU unit receives input of an ON signal or an OFFsignal of an input device as IN data, performs a logical calculation ofthe input ON/OFF information using the user program, outputs thecalculation result to an output device as OUT data. This output servesas an operation instruction to the output device and causes the outputdevice to operate. The above-described process is repeated cyclically,and thus a production facility is controlled.

Standard PLCs connected to a network constitute a communication systemand transmit/receive data via the corresponding communication units. Inthis regard, at least one of the plurality of PLCs serves as a masterPLC and manages the communication over the network, while the other PLCs(also referred to as “slave PLCs” in the present example) perform datacommunication with each other as instructed by the master PLC.

A safety PLC incorporates a self-diagnostic function in terms of safetyand thus ensures a high degree of reliability with respect to thecontrol thereof. The safety PLC includes such a function (fail-safefunction) that if an abnormality is detected as a result ofself-diagnosis of the safety PLC, the safety PLC forcibly performs safecontrol so as to prevent the control of the safety PLC itself fromleading to danger.

The safety PLC includes a communication master function of performingnetwork communication with a safety I/O terminal and sometimes may bereferred to as “safety master”. Moreover, the safety I/O terminal mayalso be referred to as “safety slave”.

The safety slave includes a function of performing network communicationwith the communication master function of the safety PLC, that is tosay, a communication slave function that is controlled in accordancewith the master. The safety slave includes a connecting terminal, and atleast one of a safety input device, such as a switch, that issues anON/OFF signal and a safety output device that constitutes an outputdestination of a control signal is connected to the connecting terminal.

Examples of the safety input device include an emergency stop switch SW,a light curtain, a door switch, a two-hand switch, and the like.Examples of the safety output device include a safety relay and acontactor. These safety input devices or safety output devices alsoconform to the standards for safety. The safety slave generates controldata based on a signal that is input from a safety device connected tothe safety slave, and transmits the generated control data to the safetyPLC by network communication.

The safety PLC and the safety slave also have basically the same typesof functions as those of the standard PLC.

The safety PLC receives input of an input signal of a safety inputdevice that is input to from a safety slave via a communication unit bynetwork communication, and performs a logical calculation with respectto ON/OFF of the input signal using a logic program that is stored inadvance. The safety PLC outputs an output signal based on thecalculation result to a safety slave via the communication unit bynetwork communication. The safety slave outputs the output signal to asafety output device. Such a series of operations is executedrepeatedly, and thus the safety PLC can control the entire systemincluding a manufacturing robot. Moreover, a safety output device, suchas a safety relay or a contactor, connected to the safety slave isconnected to a manufacturing robot, a processing machine, a cuttingmachine, or the like. The manufacturing robot or the like is operatedwhen a contact of the relay or the contactor is turned on, and themanufacturing robot or the like is stopped when the contact is turnedoff. Thus, the safety PLC executes control regarding stopping of theoperation of an operating robot or the like, which is an object to beultimately controlled, by performing ON-OFF control of a safety outputdevice.

FIG. 2 is a block diagram that schematically shows a functionalconfiguration of the master PLC 20.

Referring to FIG. 2, the master PLC 20 includes a control section 124, anonvolatile memory 122, an internal memory 126, and a communicationsection 128. These functions are realized by combining a plurality ofunits, for example, a CPU unit, a communication unit, and the like.

The control section 124 is constituted mainly by a microprocessor or thelike, and centrally manages the entire PLC.

A transmission data designation table, for example, is stored in thenonvolatile memory 122. The contents of this transmission datadesignation table may be changed by the development support device (PC10) executing a predetermined tool function. The transmission datadesignation table contains, for example, information on PLCs and thelike that constitute transmission destinations of transmission data, theinformation being associated with the transmission data. Datacommunication or the like between PLCs is executed in accordance withthis table.

The internal memory 126 relays communication between the control section124 and the communication section 128. A transmission or receivingbuffer is stored in the internal memory 126. Moreover, the internalmemory 126 is also used as a working memory.

The communication section 128 is constituted by a transmitter-receivercircuit. The communication section 128 transmits transmission datastored in the transmission buffer in the internal memory 126 to anotherPLC, and receives transmission data from other PLCs (slave PLC 22, slavePLC 24, and the like) and stores the data in the receiving buffer in theinternal memory 126. The reception data that is thus stored in thereceiving buffer in the internal memory 126 is read out by the controlsection 124 at an appropriate timing and used for execution of a userprogram. Also, the transmission data stored in the transmission bufferin the internal memory 126 is read out by the communication section 128at an appropriate timing and transmitted to the slave PLC 22 or theslave PLC 24 over the network 26.

Note that although the functional configuration of the master PLC isdescribed schematically here, the slave PLC as well as the safety masterand the safety slave, which will be described later, also have basicallythe same functional configuration as that described above, and areconfigured to be capable of data communication with various devices.

In the present example, it is assumed that the master PLC and the slavePLCs each record communication log entries during data communication(communication processing) and store the communication log entries inthe nonvolatile memory 122. The communication log entries include timeinformation of the communication processing, information regarding thecommunication state (e.g., communication has been performedsuccessfully, or an abnormality has occurred), and the like.

FIG. 3 is a block diagram that schematically shows a hardwareconfiguration of the PC 10 according to Embodiment 1.

Referring to FIG. 3, the block diagram shown represents a typicalconfiguration example.

The PC 10 includes at least a CPU 11 that centrally controls the entiredevice, an input operation section 12 for input operation includingmouse operation, keyboard operation, and the like, a display section 13that performs display processing, a working RAM 14 that is used foroperation input processing, predetermined calculation processing, imageprocessing with respect to a display screen, and the like, acommunication section 16 that manages an interface for externalcommunication, and a storage device 15. The storage device 15 stores thesupport program for performing maintenance work on the PLCs of thecommunication system of the information processing device 10, andvarious types of processing of the present application are executed byreading this program.

The above-described various sections are configured in such a manner asto be connected to an internal bus 17.

Note that as described above, the PC 10 may be a development supportdevice that is used in designing a PLC constituting the system.Specifically, the PC 10 may be configured by incorporating predeterminedtool software into a personal computer. The PLC that has been designedusing the development support device is downloaded to each PLC, and thusvarious functions can be realized. In addition, it is also possible toexecute the processing of the present example by providing a functionfor diagnosing whether an abnormality occurs in the communication systemas part of the functions of the development support device.

FIG. 4 is a diagram illustrating functional blocks that are executed bythe CPU 11 of the PC 10 according to Embodiment 1.

Referring to FIG. 4, in the present example, the PC 10 includes a logentry acquiring section 102 that acquires communication log entries fromthe PLCs as history information regarding the communication state, a logentry rearranging section 104 that rearranges the acquired communicationlog entries, a log entry extracting section 106 that extracts logentries from the rearranged communication log entries as necessary, anda log entry display section 108 that displays the extracted log entries.

FIG. 5 is a diagram illustrating a case in which a communicationabnormality has occurred in the communication system according toEmbodiment 1.

Referring to FIG. 5, in the communication system, a case in which datais transmitted from the slave PLC 22 to the slave PLC 24 via the masterPLC 20 is described in the present example.

Moreover, in the present example, it is assumed that a communicationabnormality has occurred during data communication from the master PLC20 to the slave PLC 24.

The PLCs record communication log entries during the data communication.In the present example, it is assumed that the master PLC 20, forexample, retains a communication log (log file) LB in whichcommunication log entries are recorded. It is assumed that the slave PLC22 retains a communication log LA. Also, it is assumed that the slavePLC 24 retains a communication log LC.

The PC 10 requests the PLCs to transmit the recorded communication logentries. Then, in response to the transmission request, the PLCstransmit the communication log entries saved in the respective PLCs tothe PC 10.

In the present example, a case in which data communication is performedwith the slave PLC 22, which is referred to as a device “A”, the masterPLC 20, which is referred to as a device “B”, and the slave PLC 24,which is referred to as a device “C”, will be described.

The communication log LA records that data has been successfullytransmitted from the device A to the device B at time T0 “Transmissionsucceeded (A→B)” and that a timeout has occurred at time T4 due to theabsence of data communication from the device C to the device A “Timeout(A←C)”.

The communication log LB records that the device B has successfullyreceived data from the device A at time T1 “Receiving succeeded (B←A)”,that data has not been successfully transmitted from the device B to thedevice C at time T2 “Transmission failed (B→C)”, and that a timeout hasoccurred at time T3 due to the absence of data communication from thedevice C to the device B “Timeout (B←C)”.

FIG. 6 is a diagram illustrating an example of communication log entriesthat are processed by the PC 10 of the communication system according toEmbodiment 1.

Referring to FIG. 6, the log entry acquiring section 102 of the PC 10acquires communication log entries from the PLCs. Specifically, in thepresent example, the log entry acquiring section 102 acquires thecommunication logs LA and LB of the master PLC 20 and the slave PLC.Note that in the present example, it is assumed that the log entryacquiring section 102 does not acquire the communication log LC from theslave PLC 24 because the communication abnormality has occurred.

The log entry rearranging section 104 of the PC 10 rearranges thecommunication log entries contained in the communication logs LA and LBin chronological order in accordance with the times (time information)contained in the respective communication log entries.

In the present example, a case in which the communication log entriesare rearranged in chronological order from time T0 up to time T4 isshown.

Then, the log entry extracting section 106 extracts, out of thecommunication log entries rearranged by the log entry rearrangingsection 104, communication log entries that have been recorded within apredetermined period of time from the occurrence of a communication logentry including communication abnormality information that indicates theoccurrence of the abnormality in communication as the communicationstate. Specifically, in the present example, it is assumed that“Transmission failed” or “Timeout” corresponds to a communication logentry that indicates communication abnormality information.

For example, communication log entries that have been recorded within apredetermined period of time (predetermined range) before and after thecommunication log entry (also referred to as “error log entry”)including the communication abnormality information are extracted as thecommunication log entries that have been recorded within a predeterminedperiod of time from the occurrence of the communication log entryincluding the communication abnormality information.

The above-described processing makes it possible to collectively displaya series of communication log entries including communication logentries (error log entries) and the like including communicationabnormality information by extracting those communication log entriesthat have been recorded within a predetermined period of time before andafter the communication log entry (error log entry) including thecommunication abnormality information, instead of extracting anddisplaying only the communication log entries that include communicationabnormality information or displaying all the communication log entries.Therefore, mutually related error conditions can be easily recognized.

Note that although a method for extracting communication log entriesthat have been recorded within a predetermined period of time relativeto an error log entry was described in the present example, a personskilled in the art can appropriately change the predetermined period oftime. Moreover, although a case in which communication log entries thathave been recorded within a predetermined period of time before andafter a communication log entry are extracted was described in thepresent example, it is also possible to extract communication logentries that have been recorded after the occurrence of an error logentry.

Modification

FIG. 7 is a diagram illustrating a case in which a communicationabnormality has occurred in a communication system according to amodification of Embodiment 1.

Referring to FIG. 7, the communication system according to themodification of Embodiment 1 further includes a safety master and asafety slave. Specifically, a case in which the safety master and thesafety slave are combined with the master PLC and the slave PLCs andthus constitute the communication system is shown. In the presentexample, the safety master and the safety slave each operate incooperation with the master PLC or one of the slave PLCs. As an example,a case in which a safety master 30 is coupled to the slave PLC 22 and asafety slave 32 is coupled to the slave PLC 24 is shown. Due to thiscoupling, the safety master 30 is connected to the network 26 via theinternal bus of the slave PLC 22 and thus performs data communication.Also, the safety slave 32 is connected to the network 26 via theinternal bus of the slave PLC 24 and thus performs data communication.

In the present example, a case in which data is transmitted from thesafety master 30 to the safety slave 32 is described. In addition, inthe present example, it is assumed that a communication abnormality hasoccurred during data communication from the slave PLC 24 to the safetyslave 32.

The PLCs record communication log entries during the data communication.In the present example, it is assumed that, for example, the master PLC20 retains a communication log LB# in which communication log entriesare recorded. It is assumed that the slave PLC 22 retains acommunication log LA#. It is assumed that the slave PLC 24 retains acommunication log LC#. It is assumed that the safety master 30 retains acommunication log LD. Moreover, it is assumed that the safety slave 32retains a communication log LE.

The PC 10 requests the PLCs to transmit the recorded communication logentries. Then, in response to the transmission request, the PLCstransmit the communication log entries saved in the respective PLCs tothe PC 10.

In the present example, a case in which data communication is performedwith the slave PLC 22, which is referred to as the device “A”, themaster PLC 20, which is referred to as the device “B”, the slave PLC 24,which is referred to as the device “C”, the safety master 30, which isreferred to as a device “D”, and the safety slave 32, which is referredto as a device “E”, will be described.

The communication log LD records that data has been successfullytransmitted from the device D to the device A at time T10 “Transmissionsucceeded (D→A)”, and that a timeout has occurred at time T20 due to theabsence of data communication from the device E to the device D “Timeout(D←E)”.

The communication log LA# records that the device A has successfullyreceived data from the device D at time T11 “Receiving succeeded (A←D)”,that data has been successfully transmitted from the device A to thedevice B at time T12 “Transmission succeeded (A→B)”, and that a timeouthas occurred at time T19 due to the absence of data communication fromthe device B to the device A “Timeout (A←B)”.

The communication log LB# records that the device B has successfullyreceived data from the device A at time T13 “Receiving succeeded (B←A)”,that data has been successfully transmitted from the device B to thedevice C at time

T14 “Transmission succeeded (B→C)”, and that a timeout has occurred attime T18 due to the absence of data communication from the device C tothe device B “Timeout (B←C)”.

The communication log LC# records that the device C has successfullyreceived data from the device B at time T15 “Receiving succeeded (C←B)”,that data communication from the device C to the device E has not beensuccessfully performed at time T16 “Transmission failed (C→E)”, and thata timeout has occurred at time T17 due to the absence of datacommunication from the device E to the device C “Timeout (C→E)”.

FIG. 8 is a diagram illustrating an example of communication log entriesthat are processed by the PC 10 of the communication system according tothe modification of Embodiment 1.

Referring to FIG. 8, the log entry acquiring section 102 of the PC 10acquires communication log entries from the PLCs. Specifically, in thepresent example, the log entry acquiring section 102 acquires thecommunication logs LA#, LB#, and LC# of the master PLC 20 and the slavePLCs, respectively. Furthermore, the log entry acquiring section 102acquires the communication log LD of the safety master 30. Note that inthe present example, it is assumed that the log entry acquiring section102 does not acquire the communication log LE from the safety slave 32because the communication abnormality has occurred.

The log entry rearranging section 104 of the PC 10 rearranges thecommunication log entries contained in the communication logs LA# to LC#and LD in chronological order in accordance with the times (timeinformation) contained in the respective communication log entries.

In the present example, a case in which the communication log entriesare rearranged in chronological order from time T10 up to time T20 isshown.

Then, the log entry extracting section 106 extracts, out of thecommunication log entries rearranged by the log entry rearrangingsection 104, communication log entries that have been recorded within apredetermined period of time from the occurrence of a communication logentry including communication abnormality information that indicates theoccurrence of the abnormality in communication as the communicationstate. Specifically, in the present example, it is assumed that“Transmission failed” or “Timeout” corresponds to a communication logentry that indicates communication abnormality information.

For example, communication log entries that have been recorded within apredetermined period of time (predetermined range) before and after acommunication log entry (also referred to as “error log entry”)including communication abnormality information are extracted as thecommunication log entries that have been recorded within a predeterminedperiod of time from the occurrence of the communication log entryincluding the communication abnormality information.

The above-described processing makes it possible to collectively displaya series of communication log entries including communication logentries (error log entries) and the like including communicationabnormality information by extracting those communication log entriesthat have been recorded within a predetermined period of time before andafter the communication log entry including the communicationabnormality information, instead of extracting and displaying only thecommunication log entries that include communication abnormalityinformation or displaying all the communication log entries. Therefore,mutually related error conditions can be easily recognized.

Note that although a case in which the safety master 30 and the safetyslave 32 are respectively coupled to the slave PLCs was described in thepresent example, the present invention is not limited to thisconfiguration. For example, a configuration may also be adopted in whichthey are coupled to the safety master 30.

Embodiment 2

In Embodiment 1 and the modification thereof, a case in whichcommunication log entries that have been recorded within a predeterminedperiod of time relative to a communication log entry includingcommunication abnormality information are extracted was described,whereas in Embodiment 2, a method for further recognizing an errorcondition in an easy manner based on the extracted communication logentries will be described.

FIG. 9 is a diagram illustrating functional blocks that are executed bythe CPU 11 of the PC 10 according to Embodiment 2.

Referring to FIG. 9, in the present example, the PC 10 includes the logentry acquiring section 102 that acquires communication log entries fromthe PLCs as history information regarding the communication state, thelog entry rearranging section 104 that rearranges the acquiredcommunication log entries, the log entry extracting section 106 thatextracts log entries from the rearranged communication log entries asnecessary, an abnormality cause identifying section 107 that identifiesthe cause of an abnormality with respect to the extracted communicationlog entries by referring to an abnormality cause analysis database,which will be described later, and a cause display section 109 thatdisplays the cause of the abnormality identified by the abnormalitycause identifying section 107. Moreover, the storage device 15 of thepresent example has the abnormality cause analysis database DB (alsoreferred to simply as “database DB”) in which the causes ofabnormalities and abnormality patterns associated therewith are stored,the abnormality patterns including at least one communication log entryincluding communication abnormality information. The database DB storesa plurality of error pattern data items DP as the abnormality patterns.In the error pattern data items DP, error causes are associated withcommunication log entry patterns attributed to the error causes. Here, acase in which a combination of a plurality of timeouts is associatedwith error causes is shown as an example.

In Embodiment 2, the abnormality cause identifying section 107 refers tothe database DB in accordance with the extracted communication logentries, thereby identifying the cause of the abnormality. Specifically,based on the extracted communication log entries including thecommunication abnormality information, the abnormality cause identifyingsection 107 refers to the database DB and determines whether an errorpattern data item DP corresponding to the pattern of the extractedcommunication log entries is present. If the error pattern data item DPis present, an error cause is identified in accordance with that errorpattern data item DP. Then, the cause display section 109 displays theidentified cause of the abnormality on the display section 13. Note thatthe number of error causes is not limited to one, and if a plurality ofcauses are present, the cause display section 109 displays the pluralityof causes.

Note that the error pattern data items DP are created in advance byanalyzing patterns of communication log entries and patterns that causeabnormalities by performing simulations, experiments, and the like.Although a case in which the error pattern data items DP are stored inthe storage device 15 in advance is described in the present example, itgoes without saying that the error pattern data items DP can also bedownloaded from a server or the like and saved.

FIG. 10 is a diagram illustrating display of a troubleshooting log thatis displayed on the display section 13 according to Embodiment 2.

Referring to FIG. 10, in the present example, a case in which the causedisplay section 109 displays the troubleshooting log on the displaysection 13 will be described.

In the present example, the communication log entries that have beenrecorded within a predetermined period of time from the occurrence ofthe communication log entry including the communication abnormalityinformation described with reference to FIG. 8 are extracted by way ofexample, and thus the communication log entries from time T10 up to timeT20 are extracted and displayed. Also, the causes of the abnormalitythat are identified based on the extraction result are shown.

Specifically, “Communication timeout has occurred during communicationwith safety slave.” is displayed as the details of the abnormality, and,in the present example, four possible causes of the abnormality areshown as examples. Note that although four possible causes are shown asexamples, the number of possible causes shown as examples may be one, ora plurality of possible causes may be displayed as examples. Moreover,the possible causes may be displayed in descending order of possibility.

Specifically, the four possible causes are as follows. (1) Abnormalityin setting: the task execution timeout time with respect to the masterPLC is set to an excessively small value. (2) Excessive noise hasoccurred. (3) A system abnormality has occurred in the master PLC. (4)Occurrence of abnormality in safety slave PLC: Some abnormality hasoccurred in this device, and process data communication has not beenproperly executed.

The display of the possible causes enables the user to easily recognizethe cause of the error. Therefore, it is possible to easily recognizethe cause of an error and easily locate a fault to be eliminated.

Note that the above display example is merely an example. Naturally, itis also possible to execute display processing in accordance with othererror pattern data items DP based on other combinations of communicationlog entries and the like.

Moreover, an application that is executable on a personal computer maybe provided as the program of the embodiments. At this time, the programaccording to the embodiments may be incorporated as part of thefunctions of various applications that are executed on the personalcomputer.

The embodiments disclosed herein should be considered as illustrative,and the present invention is not limited only to the foregoingdescription. The scope of the present invention is indicated by theappended claims, and all changes which come within the meaning and rangeof equivalency of the claims are intended to be embraced therein.

INDEX TO THE REFERENCE NUMERALS

10 . . . information processing device; 11 . . . CPU; 12 . . . inputoperation section; 13 . . . display section; 14 . . . RAM; 15 . . .storage device; 16, 128 . . . communication section; 17 . . . internalbus; 20, 22, 24 . . . PLC; 26 . . . network; 30 . . . safety master; 32. . . safety slave; 102 . . . log entry acquiring section; 104 . . . logentry rearranging section; 106 . . . log entry extracting section; 107 .. . abnormality cause identifying section; 108 . . . log entry displaysection; 109 . . . cause display section; 122 . . . nonvolatile memory;124 . . . control section; 126 . . . internal memory.

1. An information processing device for collecting information on anoperating state of a communication system formed of a master device formanaging communication over a network and at least one slave device thatis connected to the network and that is capable of performingcommunication as instructed by the master device, wherein the masterdevice and the slave device record communication log entries regardingtime information and a communication state in accordance withcommunication processing, the information processing device comprising:an acquiring section configured to acquire communication log entriesfrom at least one of the master device and the slave device; a log entryrearranging section configured to rearrange the acquired communicationlog entries based on the time information; and a log entry extractingsection configured to extract, out of the communication log entriesrearranged by the log entry rearranging section, any communication logentry recorded within a predetermined period of time from occurrence ofa communication log entry including communication abnormalityinformation that indicates occurrence of an abnormality in communicationas the communication state.
 2. The information processing deviceaccording to claim 1, further comprising: a display section configuredto display the extracted communication log entries.
 3. The informationprocessing device according to claim 1, wherein the communication systemis provided with a safety slave device that is connected to a devicerelated to safety and a safety master device for managing the safetyslave device, the safety slave device or the safety master device isconnected to at least one of the master device and the slave device, thesafety master device is configured to issue an instruction to the safetyslave device via the master device, the safety master device and thesafety slave device record communication log entries regarding the timeinformation and the communication state in accordance with thecommunication processing, and the acquiring section further acquirescommunication log entries from at least one of the safety master deviceand the safety slave device.
 4. The information processing deviceaccording to claim 1, further comprising: an abnormality cause analysisdatabase configured to store a cause of an abnormality and anabnormality pattern associated therewith, the abnormality patternincluding at least one communication log entry including communicationabnormality information; and an abnormality cause identifying sectionconfigured to identify a cause of the abnormality with respect to theextracted communication log entries by referring to the abnormalitycause analysis database.
 5. A method for controlling an informationprocessing device that collects information on an operating state of acommunication system formed of a master device that managescommunication over a network and at least one slave device that isconnected to the network and that is capable of performing communicationas instructed by the master device, wherein communication log entriesregarding time information and a communication state are recorded in themaster device and the slave device in accordance with communicationprocessing, the method comprising the steps of: acquiring communicationlog entries from at least one of the master device and the slave device;rearranging the acquired communication log entries based on the timeinformation; and extracting, out of the rearranged communication logentries, any communication log entry recorded within a predeterminedperiod of time from occurrence of a communication log entry includingcommunication abnormality information that indicates occurrence of anabnormality in communication as the communication state.
 6. A controlprogram of an information processing device that collects information onan operating state of a communication system formed of a master devicethat manages communication over a network and at least one slave devicethat is connected to the network and that is capable of performingcommunication as instructed by the master device, the control programbeing executable on a computer of the information processing device,wherein communication log entries regarding time information and acommunication state are recorded in the master device and the slavedevice in accordance with communication processing, the program causingthe computer to execute processing comprising the steps of: acquiringcommunication log entries from at least one of the master device and theslave device; rearranging the acquired communication log entries basedon the time information; and extracting, out of the rearrangedcommunication log entries, any communication log entry recorded within apredetermined period of time from occurrence of a communication logentry including communication abnormality information that indicatesoccurrence of an abnormality in communication as the communicationstate.